Even though an 8.2 magnitude earthquake hit northern Chile as recently as April 2014, researchers believe the plate boundary in that region is still capable of hosting even greater shocks in the near future.
The seismic gap theory can identify regions of elevated hazard by looking at recent activity, or lack thereof, in various regions of the fault, the U.S. Geological Survey reported. The theory had previously identified the northern Chile subduction zone as as area of future concern for 8.0 and over magnitude earthquakes.
Researchers found that while the 2014 Iquique earthquake occurred within an activity gap, it did not fill the entire space of this gap; this means the potential for an 8.0 magnitude earthquake is still high in this area.
Certain sections of the subduction zone have not ruptured in over 150 years, so it is possible for future megathrust earthquakes to both the north and sour of the Iquique sequence.
"As well as revealing interesting aspects of earthquake interactions in this subduction zone, our study indicates that the occurrence of the 2014 magnitude 8.2 event does not mean short-term hazard of large earthquakes in northern Chile has decreased - in fact, while we unfortunately cannot predict the timing of such events, similar-sized or indeed larger earthquakes are possible in the near future," said USGS research geophysicist Gavin Hayes.
A review of a long-term earthquake catalogue revealed stresses were increasing along the plate boundary in years leading up to the earthquake causing it to start to unlock through the foreshock series' immense stress, GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre reported.
The 8.1 magnitude mainshock of the earthquake occurred down a 150 kilometer long central piece of the, leaving two large segments to the north and south intact.
"The foreshocks skirted around the central rupture patch of the mainshock, forming several clusters that propagated from south to north," GFZ scientist Bernd Schurr said.
The findings were published in a recent edition of the Nature Advance Online Publication.
